For the purpose of authentication of whether or not a certain article is genuine, an authenticating seal has often been applied to that article. For instance, a hologram seal comprising a seal form of hologram has been used frequently, because advanced technologies are needed for hologram fabrication. Now that holograms have been long used, however, there are no small illegal attempts. In this sense, there is mounting demand for holograms that are more difficult to forge.
Another demand for holograms is to be capable of being authenticated by simple means. For instance, take credit cards that are a sort of ID cards. A variety of credit cards are available and used in various applications. However, judgment of whether or not a certain credit card is genuine is often implemented by salesclerks, rather than experts, and so an authenticating method that is simpler and takes no much time is still in great need.
So far, it has been proposed to metalize a part of hologram by evaporation means thereby giving diffracted light or a hologram image depending on the metalized portion (see Patent Publication 1).
It has also been tried to combine hologram with colesteric liquid crystals thereby adding their effect of changing in colors depending on the angle of viewing as well as their polarization effect. For instance, there has been an authenticating structure put forward wherein a fine hologram relief is formed on a cholesteric liquid crystal layer itself, and the fine hologram relief is filled up with a thermosetting resin or ionized radiation-curable resin to make up for heat resistance, preferably with a layer colored in a dark or deep color (see Patent Publication 2).    Patent Publication 1: JP(A)4-104188    Patent Publication 2: JP(A)2003-185835
With the invention set forth in Patent Publication 1, a pattern resulting from the presence or absence of the metalized layer could be added to the hologram, and with the invention disclosed in Patent Publication 2, the effect of cholesteric liquid crystals on color changes depending on the angle of viewing could be added to the hologram. However, in the former, there are merely areas where the hologram can be seen and areas where the hologram cannot, and in the latter, the hologram is not only hard to see but also there are only the effects of the cholesteric liquid crystal layer added to the entire surface of the hologram. In either case, therefore, more complicated appearance and ease of authentication are still in need.